Timepiece setting mechanisms are well known for timepieces having a train of gear members, wherein a manually actuated stem is moved from a detented disengaged position so that a stem setting pinion on the stem engages crown teeth arranged on one of the gear members when the stem is in a second detented position. Subsequently, the stem setting pinion and stem may be rotated by a watch crown exterior to the timepiece case. Such stem setting mechanisms have long been known in mechanical or spring driven timepieces and are used as well in electronic timepieces of the "analog type". The latter incorporate a stepping motor driven by pulses from an integrated circuit having a quartz oscillator time base.
One problem in the prior art, especially in the case of quartz analog wristwatches where the gear with crown teeth resist rotation due to holding torque of the stepping motor, is the possibility of damaging the meshing gear teeth at the time of engagement. In order to avoid this possibility, the engaging teeth have sometimes been bevelled or relieved on the engaging side of either the stem setting pinion or the crown gear to facilitate engagement by forcing a slight rotation of either the stem setting pinion or the crown gear as the gears are engaged. Examples of detented manually actuated stems with a stem setting pinion on the stem arranged to engage or disengage crown gear teeth are shown by way of example in U.S. Pat. No. 3,360,922, issued Jan. 1968 to D. J. Rogers and U.S. Pat. No. 3,866,407, issued Feb. 18, 1975 to Wuthrich, the latter assigned to the applicant's assignee.
In the case of the prior art stem setting mechanisms, it has been the conventional practice to arrange the stem setting pinion axis to intersect the crown gear axis, thereby moving the stem in a radial direction with respect to the crown gear. For some timepieces, it is desirable to support the stem by an extension which is suitably supported in the frame. If the crown gear has a small diameter, the stem extension and its supporting means is likely to interfere with the crown gear spindle.
Accordingly, one object of the present invention is to provide an improved setting mechanism for a timepiece which reduces possibility of damaging the setting gears at the time of engagement
Another object of the invention is to provide an improved arrangement for a stem setting mechanism employing a stem extension support.
Still another object of the invention is to provide an improved setting mechanism for a quartz analog timepiece when the minute wheel includes a set of crown teeth engaged by a stem setting pinion on an axially slidable, rotatable, detentable, manually actuated stem.